Protesters in Cairo's Tahrir Square react after President Mohammed Morsi was ousted by the military on Wednesday. The head of Egypt's armed forces, Gen. Abdel Fattah al-Sisi, issued a declaration suspending the constitution and appointing Egypt's chief justice as interim head of state.

Members of the Muslim Brotherhood and supporters of Morsi react after the Egyptian army's statement outing Morsi, at the Raba El-Adwyia mosque square in Cairo. Morsi responded via twitter that his removal "represent[s] a full coup categorically rejected by all the free men of our nation."

Protesters in Cairo's Tahrir Square react after President Mohammed Morsi was ousted by the military on Wednesday. The head of Egypt's armed forces, Gen. Abdel Fattah al-Sisi, issued a declaration suspending the constitution and appointing Egypt's chief justice as interim head of state.

A huge celebration has begun in Egypt's Tahrir Square, after army chief Gen. Abdel Fattah al-Sisi proclaimed that Mohammed Morsi is out as president and the country's constitution has been suspended. The new plan calls for Egypt's chief justice to lead an interim government and set a date for early presidential elections.

The military announced the transition in a TV broadcast in which al-Sisi was accompanied by Mohamed ElBaradei, the leader of the liberal opposition to Morsi, as well as the imam of Cairo's Al-Azhar mosque and the pope of the Coptic Church. Members of the youth group that led the charge against Morsi also attended.

Mass protests that have persisted since Sunday prompted Egypt's military to replace Morsi, who was democratically elected last year. The military had set a deadline of today for Morsi to come to a compromise agreement with his opponents. Instead, he remained defiant, insisting he would not resign.

The coup led the U.S. State Department to warn U.S. citizens today "to defer travel to Egypt and U.S. citizens living in Egypt to depart at this time because of the continuing political and social unrest."

We're continuing to follow developments in the story.

Morsi and his supporters said earlier that they saw the army's demand as a de facto threat of a coup. On Morning Edition, NPR's Cairo bureau chief Leila Fadel said Morsi's Muslim Brotherhood supporters had vowed to "face a coup with martyrdom."

The anti-Morsi protesters who flooded Egyptian cities' streets in recent days said they wouldn't stop until the president resigned, Leila reported. Among the things fueling the protesters' discontent: the country's deep economic problems.

The military, meanwhile, has said it will "sacrifice even our blood for Egypt and its people, to defend them against any terrorist, radical or fool."

Gehad el-Haddad, a spokesman for the Muslim Brotherhood party, said Morsi was under house arrest at a Presidential Guard facility where he had been residing, and 12 presidential aides also were under house arrest, according to The Associated Press.

Update at 7 p.m. ET: President Obama Says U.S. Is 'Deeply Concerned' By Ouster

Egypt's military must preserve the rights and safety of its citizens, President Obama says, in a statement issued Wednesday in which he called the situation in Egypt "very fluid."

"The voices of all those who have protested peacefully must be heard — including those who welcomed today's developments, and those who have supported President Morsy," Obama said. "In the interim, I urge all sides to avoid violence and come together to ensure the lasting restoration of Egypt's democracy."

The president also said he has order a review of the ouster's "implications under U.S. law for our assistance to the Government of Egypt."

The State Department this afternoon warned U.S. citizens "to defer travel to Egypt and U.S. citizens living in Egypt to depart at this time because of the continuing political and social unrest."

Announcing the Travel Warning, the State Department added that it has ordered non-emergency U.S. government employees and their families to leave Egypt.

Update at 5:30 p.m. ET: No U.S. Aid After Coup, Leahy Says

The question of how the U.S. might adjust its political and financial dealings with Egypt could be a difficult one.

While acknowledging that Morsi's government "has been a great disappointment to the people of Egypt," Sen. Patrick Leahy, the chairman of the Budget Committee for the State Department and Foreign Assistance, stated today that U.S. funds cannot continue after a coup.

In a statement issued Wednesday afternoon, Leahy says he hopes the military keeps its promise to allow civilians to govern the country. But he also said that "our law is clear: U.S. aid is cut off when a democratically elected government is deposed by military coup or decree."

While saying his committee would wait to see how things develop in Egypt, Leahy added, "As the world's oldest democracy, this is a time to reaffirm our commitment to the principle that transfers of power should be by the ballot, not by force of arms."

When the State Department outlined U.S. policy after a coup took place in Fiji in 2006, it said that while providing military and peacekeeping aid was forbidden, some aid could continue, "such as programs that deal with environmental issues, health issues such as HIV/AIDS and avian flu, counterproliferation, supporting refugees and support to non governmental organizations (NGOs)."

Update at 4:05 p.m. ET: Calling It A 'Coup'

Morsi's ouster may present a prickly situation to the U.S. government, reports NPR's Michele Kelemen, who notes that U.S. officials might hesitate to call the incident a coup.

"The U.S. would have to cut off aid to Egypt's military if it does determine this was a coup," Michele reports. She cites today's daily briefing at the State Department:

"Spokesperson Jen Psaki was asked to spell out the department's definition of a coup. She would only say, 'I'm happy to get you that, but I wouldn't ascribe, you know, specific words. Each scenario is different. And if you need our specific, formal, government definition, we'll get that around to everybody.' "

As for reaction elsewhere in Washington, the White House says Obama "is being updated by the National Security Staff" on the situation in Egypt, NPR's Scott Horsley reports.

Update at 3:45 p.m. ET: Morsi Rejects Coup, Urges Peace

Mohammed Morsi is using his official presidential Twitter account to respond to his removal from power by Egypt's military, which he says "represent a full coup categorically rejected by all the free men of our nation."

Morsi says the move "turns Egypt backwards."

But Morsi also"urges everyone to adhere to peacefulness and avoid shedding blood of fellow countrymen," according a tweet posted just before 3:40 p.m. ET.

Update at 3:15 p.m. ET: Morsi Is Out, Military Says

Military chief Gen. Abdel Fattah al-Sisi says Morsi is out as president and that the country's constitution has been suspended. Egypt's chief justice will hold power during the transitional period and set a date for early presidential elections.

A new political "roadmap" for Egypt's shift from President Mohammed Morsi's rule to an interim government will be announced shortly, reports the Middle East News Agency, the official state agency. As of now, there has been no public reaction from Morsi and his party, the Muslim Brotherhood.

Egyptian state radio said that the transition plan is expected to be announced within an hour by Mohamed ElBaradei, the leader of the liberal opposition to Morsi, along with two clerics: the imam of Cairo's Al-Azhar mosque and the pope of the Coptic Church. Members of the military and of the youth group that has led the charge against Morsi are also expected to attend.

Reuters reports that the plan, backed by Egypt's military, calls for new presidential and parliamentary elections, after an interim rule. Citing the army's Facebook page, Reuters says the army chief met with political and religious leaders Wednesday evening.

Update at 2 p.m. ET: U.S. Sides With The People, State Dept. Says

Insisting that the U.S. will not take sides in Egypt's conflict, U.S. State Department spokesperson Jen Psaki says, "We're on the side of the Egyptian people."

Psaki told reporters at today's daily news briefing that all sides of the clashes in Egypt need to listen to one another, and to the Egyptian public. She also said the U.S. is monitoring events closely, saying officials are "very concerned."

On Tuesday, Psaki said, "The reports that we have been urging early elections are inaccurate."

Following up on the reports that Morsi has been banned from traveling, Egyptian State TV is saying that all charter flights have been grounded — which would effectively bar travel by any officials.

Meanwhile, troops and equipment have been seen moving toward places in Cairo where Morsi's supporters have gathered and Reuters says "barbed wire [and] barriers" have been put around the "barracks where President Morsi [is] working. The wire service adds that the army says it is "securing the area only."

Update at 12:30 p.m. ET. Reports Of Ultimatum And Travel Ban For Morsi:

"A senior adviser to the president says an ultimatum was given to Morsi" by the military, NPR's Leila Fadel reports from Cairo. He was reportedly told: "resign or else." That adviser also tells Leila that Morsi refused. Note: The army has not commented on such reports and it's worth noting that the account is coming from the Morsi camp, which has an incentive to try to shape the story's narrative.

"For the sake of Egypt and for historical accuracy, let's call what is happening by its real name: Military coup," writes Essam al-Haddad, Morsi's assistant for foreign relations and international cooperation, on his Facebook page.

Those may be among "the last lines I get to post on this page," he also says.

The Egyptian president believes it would be better to defend Egypt's democracy and die "standing like a tree" than to step aside, spokesman Ayman Ali has told Reuters.

Update at 8:05 a.m. ET. ElBaradei Reportedly Meets With Military:

According to Reuters, "Egyptian liberal opposition leader Mohamed ElBaradei met army chief General Abdel Fattah al-Sisi on Wednesday, two political sources said, hours before an army deadline for Islamist President Mohamed Mursi to yield to mass protests or quit. ... 'In the meeting, ElBaradei will urge the armed forces to intervene to stop the bloodshed,' one opposition source said."